What’s special about New Zealand’s native trees and forests?
— Extracted from Field Guide to New Zealand Native Trees by John Dawson
New Zealand’s native trees and forests are unique. They look, smell and feel like no other forests, which is not surprising, as more than 80% of the c. 2400 native species of conifers, flowering plants and ferns in the flora as a whole occur nowhere else in the world. This remarkably high level of endemism is one of the reasons for New Zealand being recognised by Conservation International as a world biodiversity hotspot.
Piper excelsum subsp. excelsum | KAWAKAWA PIPERACEAE
The leaves of kawakawa are often conspicuously riddled with holes and notches – the result of browsing by the caterpillars of a native moth, Cleora scriptaria. The hot-tasting leaves are poisonous to most insects and so are avoided, but the larva of this moth is immune and obviously thrives on the diet.
Distribution & Habit
Found in lowland forest throughout the North Island, except in colder inland localities; in the South Island, in the west south to Okarito and in the east to Banks Peninsula; also on the Chatham Islands.
Size
A shrub to small (up to 6 m tall) tree, with a trunk up to c. 6 cm or more in diameter.
Bark
Smooth and brownish black.
Foliage & Habit
Leaves are alternate, smooth-margined, shiny, heart-shaped, 5-10 x 6-12 cm, with seven principal veins radiating from near the base; usually riddled with holes. Branchlets, leaf stalks and veins are wine red to purple-black; leaf stalks have strongly sheathing bases. In forest understorey, kawakawa is a small tree with spindly stems, with distinctive swollen joints, arising from near the ground; older canes are brownish black.
Flowers & Fruits
Inflorescences are spikes (like slender erect candles), often paired, with male and female spikes on different plants. Flowers are stalkless, tiny and interspersed with rounded scales; male flowers have just a few stamens, females a single green ovary each. Fruitlets are small, orange to yellow, with some fusing together and some fusing with the now-fleshy axis of the spike. In the North Island, flowering and fruiting occur in all seasons; in the South Island, flowering is in spring and summer, and fruiting in summer and autumn.
Distinguishing Features
- Branches and stems are cane-like with swollen joints.
- Leaves are glossy and heart-shaped.
- Inflorescences and fruiting structures are solid spikes.
